fix link

Author: hexaeder

docs/src/data_structure.md

@@ -20,7 +20,7 @@ A typical workflow is:
 
 1. Set default values in the models using the metadata (see [Metadata](@ref)).
 2. Create a network (see [Network Construction](@ref)).
-3. Generate a state `s = NWState(nw)` which will be prefilled with the default values from the component metadata (see [SymbolicIndexing](@ref)).
+3. Generate a state `s = NWState(nw)` which will be prefilled with the default values from the component metadata (see [Symbolic Indexing](@ref)).
 4. Change the values of `s`, i.e., `s.v[1,:x] = 1.0`: This changes the **underlying flat array** but not the metadata of the models.
 5. Build a problem with the updated flat arrays using `uflat(s)` and `pflat(s)`.